Apparatus and method for assembling a split sleeve onto a shaft

ABSTRACT

An apparatus and method for assembling a split sleeve onto a shaft. The split sleeve apparatus provides a first and second arcuate portion with each having a partial cylindrical configuration. The first and second arcuate portions have at least one finger extending circumferentially outward from their opposing ends. The at least one finger from each of the first and second arcuate portions complementarily engage one another to form a continuous cylinder. At least one aperture extends longitudinally through the at least one finger of the first and second arcuate portions. A dowel rod extends through the at least one aperture for connecting the first and second arcuate portions to form the cylinder. The first and second arcuate portions are fabricated from a material having heat expansion characteristics that allow the material to expand when heated during assembly and to contract when cooled creating an interference fit with the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

TECHNICAL FIELD

The present disclosure relates to an apparatus and method for assemblinga split sleeve onto a shaft, and more particularly, a split sleeveapparatus that may be mounted to a cylindrical shaft by heating andconnecting the two halves of the split sleeve apparatus when placed onthe shaft and allowing the split sleeve apparatus to cool on the shaftand create an interference fit on the shaft with no additionalconnectors and/or machining.

BACKGROUND

Bearings are commonly used to allowed constrained relative movementbetween two or more parts, typically, rotary or linear movement.Hydrodynamic bearings have no “rolling” components and typically includea shaft rotatably received within a hole. The hole may be defined withina structural component, such as a portion of a machine or may be definedinside a bearing insert or housing.

Hydrodynamic bearings may be lubricated to reduce the friction between ajournal, which may comprise an outer circumference of the shaft, and thebearing insert wall, thereby allowing the shaft to rotate efficientlyagainst the non-moving bearing surface. However, in many applications,it may be necessary to place a sleeve over the shaft to act as a journalinside the bearing insert. The sleeve protects the shaft surface fromabrasion and the normal wear caused by hydrodynamic bearings. Moreover,a sleeve may be used to replace or overlap the damaged portion of theshaft and prolong the life of the bearing. However, to effectively actas a journal inside the bearing insert, it is often desired to secure orconnect the sleeve to a predetermined position on the shaft.

In some applications, a sleeve having an integrated locking collar isemployed to both protect the shaft and secure the sleeve on the shaft.Such “locking sleeves” typically include a sleeve portion and a collarportion, wherein set screws are threaded into the collar portion toengage the shaft at different radial positions on the shaft. However, inoperating environments that include frequent temperature cycling or thatimpose large amounts of lateral movement on the shaft, the setscrewsoften vibrate loose or shear, thereby resulting in damage to the shaft.

In other applications, it is known to heat a one-piece sleeve fabricatedfrom a material, such as metal, having thermal expansion properties thatallows the material to expand upon being heated and then contract uponbeing cooled. The one-piece sleeve is slid over and positioned onto theshaft. Once the sleeve is properly positioned, the sleeve is allowed tocool, thereby shrinking the sleeve onto the shaft and creating aninterference fit with the shaft. Although the shrinking of the sleeveonto the shaft is an effective method of securing the sleeve to theshaft without connectors or setscrews, one piece sleeves can only beutilized on the end of a shaft or where the end of the shaft isaccessible to slide the one-piece sleeve onto the shaft. Thus, this typeof design and application cannot be utilized where the end ormid-portion of the shaft is not accessible, such as when repairing orreplacing the sleeve without rebuilding or tearing down the machineryand equipment for which the shaft is utilized.

In those situations in which the end of the shaft is not accessible, ithas been known to utilize a two piece sleeve design such that the twopiece sleeve is assembled to a mid-portion of the shaft without havingto slide the sleeve over the end of the shaft. Previous methods forassembling the two-piece sleeve onto the shaft include heating and overlapping two halves of the two-piece sleeve onto the shaft and weldingtogether the ends of the two halves of the two piece sleeve. Once thesleeve cools, the sleeve shrinks onto the shaft, thereby creating aninterference fit as described above. However, since the finish on thesleeve is critical due to the sleeve rotating on the hydrodynamicbearing, the outer diameter of the sleeve must be machined to a desiredfinish and size. Since these applications are intended to be utilized inthe field where the shaft remains assembled to its respective equipmentor machinery, the machining of the sleeve must take place in the field.Machining in the field is costly and time consuming, thereby creatinginefficiencies that are undesirable in an industrial environment.

It would be desirable to provide an apparatus and method for installinga sleeve onto a mid-portion of a shaft that remains in the field withouthaving access to the ends of the shaft. In addition, it would bedesirable to provide an apparatus and method for installing a sleeveonto a mid-portion of a shaft without the need for connectors,setscrews, welds, and machining of the sleeve in the field.

SUMMARY

The present disclosure provides a split sleeve apparatus for assemblingto a shaft. The split sleeve apparatus provides a first arcuate portionand a second arcuate portion with each portion having a partialcylindrical configuration and opposing circumferential ends. The firstarcuate portion and the second arcuate portion each have at least onefinger extending circumferentially outward from their opposing ends. Theat least one finger from each of the first and second arcuate portionscomplementarily engage one another to form a continuous cylinder. Atleast one aperture extends longitudinally through the at least onefinger of the opposing ends of each of the first and second arcuateportions. A dowel rod extends through each of the at least one aperturefor connecting the first and second arcuate portions to form thecontinuous cylinder.

The first and second arcuate portions of the split sleeve apparatus arefabricated from a material having heat expansion characteristics thatallow the material to expand when heated and to contract when cooled.The material may be fabricated from a stainless steel.

Each of the at least one finger of the first and second arcuate portionshas a rectangular, arcuate configuration with rounded corners formed ona free end of each of the at least one finger. Each of the opposing endsof the first and second arcuate portions has a corresponding recess forcomplementarily receiving each of the at least one finger. Each of theat least one finger has a circumferential recess formed on the innerdiameter of each of the at least one finger extending from a free end ofthe at least one finger. The recess formed in each of the at least onefinger extends from the free end to a mid-portion of the at least onefinger.

Each dowel rod of the split sleeve apparatus has an end extending beyondthe first and second arcuate portions, and the end of each dowel rod hascircumferential recesses for engaging and handling the split sleeveapparatus. A pair of dowel rods may extend through apertures provided ateach of the opposing ends of the first and second arcuate portions.

Each of the first and second arcuate portions of the split sleeveapparatus has a semi-cylindrical configuration. The first and secondarcuate portions may be mirror images of one another.

The method for assembling the split sleeve apparatus onto a shaft maycomprise the steps of providing a first arcuate portion and a secondarcuate portion, wherein the first and second arcuate portions have apartial cylindrical configuration with circumferential opposing endshaving at least one finger extending from the opposing ends of the firstand second arcuate portions. The method further includes providingapertures extending longitudinally through the at least one finger ofthe opposing ends of the first and second arcuate portions. The firstand second arcuate portions are heated to allow the first and secondarcuate portions to expand. The first and second arcuate portions areplaced over the shaft, and the at least one finger on the opposing endsof the first and second arcuate portion complementarily engage oneanother to form a continuous cylinder over the shaft. The dowel rods areinserted into the apertures provided in the first and second arcuateportions. The first and second arcuate portions are cooled to allow thefirst and second arcuate portions to shrink and create an interferencefit on the shaft.

The method of assembling the split sleeve apparatus to the shaftincludes fabricating the first and second arcuate portions from amaterial having heat expansion characteristics that allow the first andsecond arcuate portions to expand upon being heated and contract uponbeing cooled. The method may further include providing stainless steelas the material for the first and second arcuate portions.

Each of the at least one finger may be provided with a rectangular,arcuate configuration with rounded corners formed on a free end of eachof the at least one finger. Each of the opposing ends of the first andsecond arcuate portions are provided with a corresponding recess forcomplementarily receiving each of the at least one finger. Each of theat least one finger are provided with a circumferential recess formed onthe inner diameter of each of the at least one finger and extending froma free end of the at least one finger.

The method may further include providing the first and second arcuateportions with a semi-cylindrical configuration. The first and secondarcuate portions may be provided with semi-cylindrical configurationshaving mirror images of one another.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read in conjunction with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not to-scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.

FIG. 1 is a top plan view of the split sleeve apparatus of the presentdisclosure;

FIG. 2 is a front isometric plan view of the split sleeve apparatus ofthe present disclosure;

FIG. 3 is an isometric view of an arcuate portion of the split sleeveapparatus of the present disclosure;

FIG. 4 is a sectional view of an arcuate portion of the split sleeveapparatus of the present disclosure;

FIG. 5 is an isometric view of a dowel rod for the split sleeveapparatus of the present disclosure;

FIG. 6 is a side isometric view of the split sleeve apparatus of thepresent disclosure;

FIG. 7 is a sectional view of the split sleeve apparatus of the presentdisclosure shown in FIG. 6 ;

FIG. 8 is a side isometric view of the split sleeve apparatus of thepresent disclosure having square fingers; and

FIG. 9 is a second view of the split sleeve apparatus of the presentdisclosure shown in FIG. 8 .

DETAILED DESCRIPTION

With reference to FIGS. 1-6 , the present disclosure provides for asplit sleeve apparatus 10 and method for assembling and connecting thesplit sleeve apparatus 10 onto the outer diameter of a shaft 12 withoutthe use of fasteners, welds, or machining. The shaft 12 may have asolid, cylindrical configuration and be fabricated from a metallicmaterial. The shaft 12 may be utilized in various types of operations,and as a nonlimiting disclosure, the shaft 12 may be a turbine shaft ina power generation facility (not shown), such as a hydroelectric powerplant (not shown). The shaft 12 may be rotationally supported by a typeof journal assembly (not shown) and/or bearing assembly (not shown), andin a nonlimiting disclosure, the bearing may be a hydrodynamic bearing.The split sleeve apparatus 10 is connected to the outer diameter of theshaft 12 and acts as a journal, whereby the split sleeve apparatus 10 islocated between the shaft 12 and the bearing such that the split sleeveapparatus 10 rotates against the bearing. The split sleeve apparatus 10acts to protect the shaft 12 from any damage to the outer diameter ofthe shaft 12 that may be caused from the shaft 12 rotating against thebearing. In addition, the split sleeve apparatus 10 may act as afinished surface for the shaft 12 to rotationally engage the bearing.

The split sleeve apparatus 10 provides a first arcuate portion 14 and asecond arcuate portion 16 that complementarily engage one another toform a continuous cylinder 17. The first and second arcuate portions 14,16 each having opposing circumferential ends 18 with similar fingers 20that extend circumferentially outward from the opposing ends 18 of eachof the first and second arcuate portions 14, 16. Recesses 22 are formedbetween the fingers 20 of both the first and second arcuate portions 14,16, and the recesses 22 have a similar shape as the fingers 20 so thatthe recesses 22 can complementarily or matingly receive the fingers 20.Apertures 24 extend longitudinally through the fingers 20 in theopposing ends 18 of the first and second arcuate portions 14, 16, anddowel rods 26 extend through the apertures 24 to connect the firstarcuate portion 14 to the second arcuate portion 16 thereby forming thecontinuous cylinder 17 of the split sleeve apparatus 10.

In order to assemble the split sleeve apparatus 10 to the shaft 12, thefirst arcuate portion 14 and the second arcuate portion 16 are formedfrom separate and independent portions of the split sleeve apparatus 10.This allows the first and second arcuate portions 14, 16 to be assembledonto a mid-portion of the shaft 12 where the ends or portions of theshaft 12 are not accessible, thereby preventing a one-piece sleeve frombeing slid over the ends of the shaft 12. Furthermore, the preexistingsleeve or journal on the shaft 12 may be replaced without having todisassemble the shaft 12 from the machinery for which the shaft 12 ismounted therein. By not having to disassemble the shaft 12 from itsassociated machinery, a significant amount of time and money can besaved in replacing the preexisting journal or sleeve. The first andsecond arcuate portions 14, 16 of the split sleeve apparatus 10 may eachhave a semi-cylindrical configuration such that the first and secondarcuate portions 14, 16 form the continuous cylinder 17 when the firstand second arcuate portions 14, 16 are assembled to one another. In analternative configuration, the first and second arcuate portions 14, 16may comprise other various circumferential portions of the cylinder 17of the split sleeve apparatus 10. For example, the first arcuate portion14 may comprise 40% of the cylinder 17 while the second arcuate portion16 may comprise 60% of the cylinder 17. So long as the first and secondarcuate portions 14, 16 form the continuous cylinder 17 when assembledtogether, the first and second arcuate portions 14, 16 may comprisevarious portions of the entire cylinder 17 of the split sleeve apparatus10.

To complementarily engage the first arcuate portion 14 to the secondarcuate portion 16 of the split sleeve apparatus 10, the fingers 20extend circumferentially outward from the opposing ends 18 of each ofthe first and second arcuate portions 14, 16. As shown in FIGS. 1-4 ,four fingers 20 may extend from each of the first and second arcuateportions 14, 16; however, the present invention is not limited to fourfingers 20, but rather, any number of fingers 20 may be utilizeddepending on the clamping force that is desired to maintain the splitsleeve apparatus 10 on the shaft 12. For instance, a larger number offingers 20 will create more shearing points with the dowel rods 26thereby creating a larger clamping force. However, a larger number offingers 20 will require the fingers 20 to be smaller in size which willdecrease the strength of each of the fingers 20. Therefore,consideration must be given as to the number and size of the fingers 20when considering the clamping force required of the split sleeveapparatus 10 on the shaft 12.

Each finger 20 has a rectangular, arcuate configuration that extendscircumferentially outward from the opposing ends 18 of each of the firstand second arcuate portions 14, 16 of the split sleeve apparatus. Eachfinger 20 has a free end 28 with rounded corners 36 formed thereon,except for the one finger 20 that extends along an outer face 30 of thefirst and second arcuate portions 14, 16, wherein the finger 20 has asquare corner 38 adjacent the outer face 30 of the first and secondarcuate portions 14, 16. In an alternative embodiment, all of thefingers 20 may have square corners 38 at their free ends 28, as shown inFIG. 6 ; however, such square corners 38 lend themselves to internalstresses that may limit the strength of the square corners 38 at thefree ends 28 of the fingers 20. The recesses 22 are formed between thefingers 20 and have complementary configurations in order tocomplementarily or matingly receive the fingers 20. Each finger 20 alsohas a circumferential recess portion 32 on the inner diameter of thefingers 20. The recess portion 32 extends from the free end 28 of thefingers 20 to a mid-portion of the fingers 20. However, the presentdisclosure is not limited to the recess portion 32 extending to themid-portion of the finger 20, but rather, the recess portion 32 mayextend to any length of the inside diameter of the finger 20. The recessportion 32 on each finger 20 ensures that no interference will occurbetween the fingers 20 and the shaft 12 when the first and secondarcuate portions 14, 16 are assembled together, as any interferencebetween the fingers 20 and the shaft 12 may cause galling between thesplit sleeve apparatus 10 and the shaft 12. Since the first and secondarcuate portions 14, 16 are designed to complementarily engage oneanother to form the continuous cylinder 17, the first and second arcuateportions 14, 16 are mirror images of one another. In other words, ifeither the first or second arcuate portions 14, 16 are flipped over, thefirst and second arcuate portions 14, 16 would have the sameconfiguration.

To hold and secure the first arcuate portion 14 to the second arcuateportion 16, the apertures 24 extend longitudinally through the outerfaces 30 and the fingers 20 of the first and second arcuate portions 14,16. Each of the apertures 24 receive one of the dowel rods 26 in orderto connect the first arcuate portion 14 to the second arcuate portion 16of the split sleeve apparatus 10. Each dowel rod 26 has an elongatedcylindrical configuration and is fabricated from a material that isconsistent with the desired clamping force of the split sleeve apparatus10 on the shaft 12, as the dowel rods 26 realize shearing forces appliedfrom the fingers 20 of the first and second arcuate portions 14, 16.Each dowel rod 26 may have annular recesses 40 at the ends of the dowelrods 26 to allow the handling of the split sleeve apparatus 10 by someform of material handling equipment (not shown). As shown in FIGS. 1-3 ,two apertures 24 are provided on each of the opposing ends 18 of thefirst and second arcuate portions 14, 16 for a total of four apertures24; however, the present disclosure is not limited to four apertures 24,but rather, any number of apertures 24 and dowel rods 26 may be utilizeddepending on the level of clamping force that is desired of the splitsleeve apparatus 10 on the shaft 12. As previously discussed, a greaternumber of dowel rods 26 will create a greater number of shear pointswith the fingers 20 of the first and second arcuate portions 14, 16,thereby increasing the clamping force of the split sleeve apparatus 10onto the shaft 12. Yet, too many apertures 24 will weaken the fingers 20thereby reducing the strength of the fingers 20. Thus, the number ofapertures 24 and the dowel rods 26 must be considered with the number offingers 20 when determining the amount of clamping force desired for thesplit sleeve apparatus 10 on the shaft 12.

In order to assemble the split sleeve apparatus 10 onto the shaft 12,the method of assembling the split sleeve apparatus onto to the shaft 12discloses heating the first and second arcuate portions 14, 16 to atemperature in which the first and second arcuate portions 14, 16 mayexpand to a desired level. This requires that the first and secondarcuate portions 14, 16 be fabricated from a material having known anddesirable thermal expansion characteristics as well as a desiredstrength. Stainless steel may be utilized as a material to fabricate thefirst and second arcuate portions 14, 16, as stainless steel has thedesired thermal expansion characteristics, hardness and strength whilealso providing a desirable smooth finish for rotatably engaging thebearing. However, the present disclosure is not limited to stainlesssteel as a material for fabricating the first and second arcuateportions 14, 16, but rather, any material having the desirable thermalexpansion characteristics, hardness, strength, and finish may beutilized.

Heating of the first and second arcuate portions 14, 16 of the splitsleeve apparatus 10 may be completed using various techniques. Forinstance, a heating blanket (not shown) may be utilized by wrapping thefirst and second arcuate portions 14, 16 with the heating blanket andallowing the heating blanket to heat the first and second arcuateportions 14, 16 to a desired temperature. Alternatively, heating ovens(not shown) may be utilized wherein the first and second arcuateportions 14, 16 are placed into the heating oven until the first andsecond arcuate portions 14, 16 reached a desired temperature. In anotherembodiment, heating rods (not shown) may be inserted into apertures 40that extend longitudinally through the first and second arcuate portions14, 16. Once the first and second arcuate portions 14, 16 reache adesired temperature, the heating rods may be removed from the apertures40 in the first and second arcuate portions 14, 16. The level of heat isdependent on the material used to fabricate the first and second arcuateportions 14, 16; however, many materials, especially metallic materials,do not require a high level of heat to expand the necessary amount. In anon-limiting disclosure, the split sleeve apparatus 10 need only expand0.006 inches in diameter in order to fit the split apparatus 10 onto theshaft 12. Upon cooling, the split sleeve apparatus will contract anequal amount, thereby creating an interference fit with the shaft 12.However, it should be noted that the present disclosure is not limitedto an expansion of 0.006 inches in diameter, but rather, the amount ofexpansion and contraction is dependent on the size of the split sleeveapparatus 10 and the thermal expansion of the material.

Once the first and second arcuate portions 14, 16 are heated to adesired temperature, the first and second arcuate portions 14, 16 of thesplit sleeve apparatus 10 are fitted over the shaft 12 by having theinner diameter of the first and second arcuate portions 14, 16 overliethe shaft 12. The first and second arcuate portions 14, 16 are fittedtogether by complementarily engaging the fingers 20 and the recesses 22of the first and second arcuate portions 14, 16. The apertures 24 in theopposing ends 18 of the first and second arcuate portions 14, 16 arealigned, and the dowel rods 26 are inserted through the apertures 24 tosecure the first and second arcuate portions 14, 16 together. The firstand second arcuate portions 14, 16 are allowed to cool, and upon doingso, the first and second arcuate portions 14, 16 contract or shrink ontothe shaft 12 thereby creating an interference fit on the shaft 12. Thecontraction of the fingers 20 causes the fingers 20 to pull the dowelrods 26 in opposite directions thereby creating shear forces at stresspoints on the dowel rods 26 while maintaining the connection between thefirst and second arcuate portions 14, 16 on the shaft 12. The materialof the dowel rods 26 is selected to support the shear forces that arecreated by the fingers 20 of the first and second arcuate portions 14,16. In a non-limiting disclosure, the configuration of the fingers 20and the dowel rods 26 shown in FIGS. 1-5 , along with the use ofstainless steel as a material for the first and second arcuate portions14, 16, may lead to a clamping force of 50 tons applied by the splitsleeve apparatus 10 to the shaft 12. Again, the clamping force may varydepending on the materials of the split sleeve apparatus 10, the numberof fingers 20, and the number of dowel rods 26.

While the disclosure has been made in connection with what is presentlyconsidered to be the most practical and preferred embodiment, it shouldbe understood that the disclosure is intended to cover variousmodifications and equivalent arrangements.

What is claimed is:
 1. A split sleeve apparatus assembled to a shaft,comprising: a first arcuate portion and a second arcuate portion eachhaving a partial cylindrical configuration and each having opposingcircumferential ends; the first arcuate portion and the second arcuateportion each having at least one finger extending circumferentiallyoutward from each of the opposing circumferential ends; the at least onefinger from each of the first and second arcuate portionscomplementarily engaging one another to form a continuous cylinderhaving a longitudinal axis; at least one aperture extendinglongitudinally through the at least one finger of the opposing ends ofeach of the first and second arcuate portions; a dowel rod extendingthrough each of the at least one aperture for connecting the first andsecond arcuate portions to form the continuous cylinder; and each of theat least one finger having a circumferential recess formed on the innerdiameter of each of the at least one finger and extending from a freeend of the at least one finger.
 2. The split sleeve apparatus as statedin claim 1, further comprising: the recess formed in each of the atleast one finger extending from the free end to a mid portion of the atleast one finger.
 3. A split sleeve apparatus assembled to a shaft,comprising: a first arcuate portion and a second arcuate portion eachhaving a partial cylindrical configuration and each having opposingcircumferential ends; the first arcuate portion and the second arcuateportion each having at least one finger extending circumferentiallyoutward from each of the opposing circumferential ends; the at least onefinger from each of the first and second arcuate portionscomplementarily engaging one another to form a continuous cylinderhaving a longitudinal axis; at least one aperture extendinglongitudinally through the at least one finger of the opposing ends ofeach of the first and second arcuate portions; a dowel rod extendingthrough each of the at least one aperture for connecting the first andsecond arcuate portions to form the continuous cylinder; and a pair ofdowel rods extending through apertures provided at each of the opposingends of the first and second arcuate portions.